A young emperor penguin stranded on a New Zealand beach after an epic detour from Antarctic has been moved to a local zoo amid growing fears for its health.

The penguin's rare 2,000-mile (3,200km) journey from Antarctica has captured the imagination of many in the south Pacific and around the world. But veterinarians and conservation officials have become so concerned about the bird they have decided to intervene.

The penguin, which was first spotted on Monday at Peka Peka beach on New Zealand's North Island, had been eating sand and small sticks of driftwood, which it had tried to regurgitate. The penguin appeared to grow more lethargic as the week progressed, and officials feared it would die if they didn't act.

Colin Miskelly, a curator at Te Papa, the Museum of New Zealand, said it made sense that a penguin might mistake sand for Antarctic snow, which emperors eat for hydration, but he had no explanation for the bird eating wood.

Miskelly was one of three experts who helped lift the penguin from the beach into a tub of ice and then onto the back of a truck. The bird was docile enough that experts didn't need to sedate it for the 40-mile journey to Wellington zoo.

Christine Wilton, the local resident who discovered the penguin while walking her dog, was back at the beach on Friday to say goodbye.

"I'm so pleased it's going to be looked after," she said. "He needed to get off the beach. He did stand up this morning, but you could tell that he wasn't happy."

Miskelly said experts at the zoo were considering sedating the penguin and putting it on an intravenous drip as they tried to nurse it back to health. Ideally, the bird would heal enough that it could be released into the wild, Miskelly said, noting that there were no facilities in New Zealand designed to house an emperor penguin long-term.

Kate Baker, a spokeswoman for the zoo, said vets would give the bird a full health check. The zoo clinic has a salt water pool that has been used in the past to nurse smaller varieties of penguins, she said.

Often sick birds require rehabilitation for a month or two before being released, Baker said, adding that some creatures with severe injuries remain in captivity.

Experts believe the penguin, which stands about 80cm (32in) high, is about 10 months old. They haven't yet determined whether it is male or female.

Emperor penguins are the tallest and largest species of penguin and can grow up to 122cm high and weigh more than 34kg (75 pounds). They typically spend their entire lives in Antarctica. It has been 44 years since an emperor penguin was last spotted in New Zealand.